Belt alignment

One of the common reasons for unplanned downtime of belt–driven machinery is pulley misalignment. Pulley misalignment can increase wear on pulleys and belts as well as increasing the noise and vibration levels, which can result in unplanned machinery downtime. Another side effect of increased vibration is premature bearing failure. This too can cause unplanned machinery downtime.

Traditional belt alignment methods
These methods, which are the most widely used, involve either using visual judgement alone or visual judgement in combination with a straight edge and/or length of string. The advantage of these traditional methods is the perceived short time needed for adjustment, although the use of a straight edge takes more time than visual judgement alone. The major disadvantage is the lack of accuracy. Some belt manufacturers recommend a maximum horizontal angle misalignment of 0,5° or even 0,25°, which is impossible to accomplish by using naked eye.

Measuring parallel (A) and angular (B) misalignment using a straight edge or a piece of string (C).
Correct alignment means that the grooves of the pulleys are aligned (D)

Laser belt alignment methods

Using a laser belt alignment tool is quicker and more accurate than traditional methods. Belt alignment tools can either align the pulley faces or the pulley grooves.

SKF has a range of three belt alignment tools that can be categorized as either aligning in the groove or aligning on the side face.

Aligning in the groove of a V-belt pulley rather than its face, allows optimum alignment of pulleys of unequal width or with dissimilar faces.

Aligning on the face is more versatile and can be used on almost all machines using V belts, banded belts, ribbed belts and most other belts as well as chain sprockets.